Many thanks to Jouke for opening the (identical) Volvo trip computer!
The identity of the transistor has been found out! Its an NB 313Y.
Now lets see if I can figure out what the circuit is supposed to do, and what else might be damaged!

It appears to be a modified TO-220 case. I am assuming it is a transistor and not a specialized semiconductor device, since the circuit board actually labels it as Q2, with the collector, base, and emitter labeled on the board.

X1 looks like the top of the letter 'N'

X2 has the bottom edge of what could be a '3', '5', 'B', 'D', 'J', 'L', 'S', or a 'U'. It is probably NOT a 'J', 'S' or an '8' because the left sied of the bottom edge might be a right angle.

X3 has a flat bottom edge, similar to a '1' or a '2'.

This produces the following chart of possibilities:

  NB313Y   This is it!

This is certainly not an exhaustive list, but its a place to start. Email me with your ideas and suggestions!